package com.example.mybatisplus.util;

import org.apache.commons.lang.StringUtils;
import org.springframework.util.ObjectUtils;



/**
 * SQL过滤
 * @author chenshun
 * @email sunlightcs@gmail.com
 * @date 2017-04-01 16:16
 */
public class SQLFilter {

    /**
     * SQL注入过滤
     * @param str  待验证的字符串
     */
    public static String sqlInject(String str){
        if(StringUtils.isBlank(str)){
            return null;
        }
        //去掉'|"|;|\字符
        str = StringUtils.replace(str, "'", "");
        str = StringUtils.replace(str, "\"", "");
        str = StringUtils.replace(str, ";", "");
        str = StringUtils.replace(str, "\\", "");

        //转换成小写
        str = str.toLowerCase();

        //非法字符
        String[] keywords = {"master", "truncate", "insert", "select", "delete", "update", "declare", "alert", "drop"};

        //判断是否包含非法字符
        for(String keyword : keywords){
            if(str.indexOf(keyword) != -1){
                //throw new Exception("包含非法字符");
            	System.out.println("包含非法字符");
            }
        }

        return str;
    }
    
    /**
     * 解决输入下划线导致全匹配的sql注入问题
     * @param param
     * @return
     */
    public static String EscpseSql(String param){
        if (!ObjectUtils.isEmpty(param)){
            return "'%\\" + param + "%'"+"escape '\\'";
        }
        return null;
    }
}
